Last week, Frankie Sanchez Jr. of San Antonio graduated from basic training for the Air Force. As tradition, the graduate stood at attention until his father, Frankie Sanchez Sr., got out of his wheelchair to tap him out.

“My husband wanted to get out of his power wheelchair and walk over to our son,” wife and mother Christy Sanchez told InsideEdition.com. “It was the most beautiful and memorable event I’ve ever witnessed in my life.”

Sanchez Sr. was diagnosed with ALS in February 2016, but has been battling the effects for more than three years. He has relied on a wheelchair since spring of that year.

“His legs are losing strength every day [and] his balance is almost gone,” Christy Sanchez said. “There is no treatment and there is no cure. We live with those thoughts every day.”

For more than 22 years, Sanchez Sr. served in the U.S. Army, which made his son’s graduation from basic training even more important, despite being hospitalized just the night before when his breathing machine stopped working.

“The doctors told my husband that without a new breathing machine, he should not leave the hospital – it would be fatal if he tried to check out and leave,” Christy Sanchez said. “We were going to miss the ceremony. We both sobbed all night long. We were completely devastated.”